If you are penetrated, don’t be killed.Survivability denotes the ability of a ship and its on-board systems to remain functional and continue designated mission in a man-made hostile environment.
[5] The naval vessels are designed to operate in a man-made hostile environment, and therefore the survivability is a vital feature required from them.
The features of the ship in this sense include platform signatures (radar, infrared, acoustic, magnetic), the defensive systems on board, such as surface-to-air missiles, EW and decoys, and also the tactics employed by the platform in countering the attack (aspects such as speed, maneuverability, chosen aspect presented to the threat).
Vulnerability is an attribute typical to the vessel and therefore heavily affected by the vessel's basic characteristics such as size, subdivision, armouring, and other hardening features, and also the design of the ship's systems, in particular the location of equipment, degrees of redundancy and separation, and the presence within a system of single point failures.
Historically, measures taken to mitigate these hazards were concerned with protecting the vehicle itself, but due to this achieving only limited protection, the focus has now shifted to safeguarding the crew within from an ever-broadening range of threats, including Radio Controlled IEDs (RCIEDs), blast, fragmentation, heat stress, and dehydration.
Threat intelligence identifying trends, emerging technologies, and attack tactics used by enemy forces enables crews to implement procedures that will reduce their exposure to unnecessary risks.
In addition, with expert, current threat intelligence, the most effective equipment can be procured or rapidly developed in support of operations.
"The capability of a system to fulfill its mission, in a timely manner, in the presence of threats such as attacks or large-scale natural disasters.